Canaloplasty is a minimally invasive surgical procedure used to treat the most common form of glaucoma. Its purpose is to lower pressure inside the eye, known as intraocular pressure (IOP). The procedure enhances the eye’s natural drainage system rather than creating a new one. Restoring the function of these existing outflow pathways helps manage the progressive damage that glaucoma can cause to the optic nerve.
The Canaloplasty Procedure
The surgery lasts under an hour and is performed under local anesthesia with sedation. It begins with the surgeon making a small incision in the sclera, the white part of the eye, to create a protective flap. This flap allows access to a deeper layer, where a second flap is made to unroof Schlemm’s canal, the eye’s main circular drainage channel. This channel is responsible for draining the clear fluid, or aqueous humor, from the front of the eye.
Once Schlemm’s canal is exposed, the surgeon introduces a microcatheter, a flexible tube thinner than a human hair. This microcatheter, which has an illuminated tip for guidance, is navigated 360 degrees around the entire length of the canal. As the catheter is withdrawn, a gel-like substance called viscoelastic is injected into the canal. This injection dilates the channel to two or three times its normal size, clearing any blockages much like a plumber’s snake clears a clogged drain.
To ensure the newly widened canal remains open, a suture is tied to the tip of the microcatheter before it is withdrawn. As the catheter is pulled out, it threads the suture through the entire length of the canal. The surgeon then tightens this suture, creating a tension that acts like a stent to hold the canal open permanently. The outer flap is sutured back into its original position.
Ideal Candidates for Canaloplasty
The procedure is designed for individuals diagnosed with open-angle glaucoma. It is often recommended for patients in the mild-to-moderate stages of the disease whose eye pressure is not adequately controlled by medications alone. People who experience side effects from glaucoma eye drops or have difficulty adhering to a medication schedule may also be considered good candidates. The surgery can also be an effective option for those with pigmentary or pseudoexfoliation glaucoma.
The procedure is contraindicated for those with angle-closure glaucoma, where the drainage angle is physically blocked, or neovascular glaucoma, which is caused by the growth of new blood vessels. Patients with significant scarring in the eye from previous surgeries or trauma may also be ineligible, as the scarring can prevent the microcatheter from successfully navigating Schlemm’s canal.
Recovery and Expected Outcomes
The recovery period for canaloplasty is faster with fewer restrictions than more invasive glaucoma surgeries. Because it does not create a full-thickness opening into the eye, there is less inflammation and a lower risk of hypotony, a condition where eye pressure drops too low. Patients wear a protective eye shield, especially at night, and are prescribed steroid and antibiotic eye drops to prevent infection and manage inflammation.
Post-operative care involves avoiding strenuous activities, swimming, and getting soap or makeup in the eye for a few weeks. Follow-up visits are scheduled to monitor eye pressure and healing, which can take up to 12 weeks. During this time, vision and intraocular pressure may fluctuate as the eye stabilizes.
Studies have shown that the procedure can lower IOP by an average of 32% two years after surgery. A benefit is the possibility of reducing or completely eliminating the need for glaucoma medications. One study found that average medication use dropped from about two different types before surgery to less than one after three years.